Manhole cover



March 24; 1925.

F. A. LOVEJOY MANHOLE COVER Filed July 26 1924 1 all 5 2 2] A from/Era.

Patented Mar. 24, 1925.

FREDERICKALDEN LOVEJQY, or wEsrRoXBUR-Y, MASSACHUSETTS.

MANHOLE COVER.

Appli cation filedq Iuly 26, 1924. Serial No. 728,421.

To all whom it may concern: I

Be it known that I, FREDERICK ALDEN Lovn oY, a citizen ofthe United States, re-

siding at 'West Roxbury, in the county -of 'Suffolk and Stateof Massachusetts, have 111- f vented certain new and useful Improvements in Manhole Covers, of which the following is a'specification.

My invention is animproved street manhole cover for sewers and the like, ofielativ'e'ly lightweight, great strength and perfect security in use.

In the drawings p Figure 1 is a top plan view 13 on line22 of Figure 1;

Figure 3 is a detail of the bolt.

'Street manhole covers as at present commonly made, are of cast iron, made of great thickness and solidity tomeet the strain of heavy trucks and the like passing over them.

Their Weight is necessarily great. Apart fromthe weight which is a burden in use, it is necessary to form them substantially smaller than the rabbete'd recess in the ring in which they fit, as,being cast, it isimprac ticable to fashion them closely or to make such a pieceto a close dimension without machining.

In use the slipping and sliding of the cover under violent impacts tends to wear the opposed parts of the cover and re- .ceiving ring and when thisfoccurs, from time to time the cover may he slid and tilted by the impact" of a wheel and forced from its position, often with damage resulting.

In modern practiceythe street manhole cover has become so heavy that it is no longerpracticable to lift them out and it is necessary to pry up one side "and then drag them out of position to one side,

It is an object of my invention to form a manhole cover of very light weight, in such a way that it is amply strong to resist all:

stresses to which it may be subjected in use;

to form it accurately to a designed size in order that it'may fit without undue movement within the rabbeted recess in the receiving ring and to reduce the cost of construction materially:

An additional object is to provide means to lockthe manhole cover in place, so that it cannot be removed from place by accident nor without asuitable tool.

My improved manhole cover is made up out of three parts, which are united into one Fi ure 2 is a medial sectional elevation- The upper surface of the manhole cover,

is formed of a pressed metal disk A, preferably with aseries Of COl1'1Ig&tlO11S,G/, and

,having about its periphery a depending flange,a g

The arch member, B, .1s formed in dished shape, having an annular flange, 6, around the rim' of the portion, 5 ofthe arch, and

having a section b at the center, preferably corrugated to combine with the corrugations of opposed portions of the plate A. Around der side of plate A, is a'flange Z).

Intermediate between the point of contact between the central portions of A and B and the peripheral portions I preferably insert and secure a stiffener ring C.

- In the lower portion of part Z1 a series of drain and ventilating apertures 79 are .formed and the plate A is provided with bolts being positioned beneath one of the apertures, a, in plate A so that the bolts may be shifted by a tool inserted through an aperture, a, in plateA, the bolts being provided with recesses, d, to receive the end of theactuating tool.

In assembling the parts the stiifener ring C is secured to the arch member B, the bolts D being first placed inplacein the designed apertures in flange b and ring C. C is preferably spot-welded to the arch member B, thus permanently securing the bolts D to the member B, with capacity for limited longitudinal movement of the bolt. The bolt D is preferably slightly curved from end to end, so that a slight friction is developed between thebolt and opposed surfaces, in order that the bolt may be held by friction in its retracted position. I

The part, B, carrying thering C and bolts D is now assembled with plate A, the bolts D being positioned beneath an aperture, a,

The ring the edge of the flange 'b, opposed to the unand parts A and C are also spot welded; I consider spt-weldingto be the preferable method of securing the various parts together, but it is obvious that other means.

of securing may be employed, as by riveting or by bolts and nuts. 1

B is a feature of; my invention as this interlocking brings to the direct support of the surface plate, A, the'arch member B, in such a fashion that any; possible deflection of-the surface plate is resisted by the tensile strength of'the flange, Z2, of'the dished archv member, to which any pressure applied to 7 metal in a thick plate, reduces the weight of the cover by halfi The use of pressed meta-l renders it possible to make the cover closely lit the. aperture in whichit rests, whereas it 1s not practicable to govern the size of cast covers closely, without machining,which is too costly. The provislon of the deep flange 6 makes impossible any accidental tilting andsliding out of'the cover. The provision of the boltsD prevents.remova-l ofthe cover by unauthorized persons, usually, children. The light weightof my manhole cover renders it easy of removal by one man, by merely inserting-a pair of'hooks in apertures, a, and lifting the plate out, after first retracting the bolts by inserting a rod through apertures, a, into a slot oi the bolts D. f

In the drawings, the thickness of the material o'fjparts A andB is necessarily shown disproportionately great, for clear ness.

I claim:

1. A compound cover, comprising an upper plate, a depending flange applied on the under peripheral part of the upper plate; an arch elcment'abutting' upon the lower part of the flange and supporting the center ofthe upper plate.

2: A" compound cover, comprising an upper plate, a depending"flange secured on the under peripheral part of the upper plate; anarch member secured at the center to the under side of the upper plate and at the outer edge of the arch member secured to the lower inside edge of the depending flange.

8. A compound cover, comprising an upper plate, corrugated at its center part; a depending flange applied on the under peripheral part of'tlie upper plate; a trimcated conical member having corrugations at its truncated surface coacting with the central corrugations on the upper plate and abutting upon the lower inside part of the depending flange and supporting the center of the upper plate.

compound cover, comprising an upper plate, corrugated at its" center part; a depending flange secured on the under peripheral part of'the upper plate; a truncated conical member having corrugations at its center coacting with the central corrugations on the upper plate and secured at its edge to the lower part of the depending flange and supporting the center of the upper plate.

5. As in claim 1 and'having also a. stiff ener ring secured to the upper plate and arch member, intermedlate their centers and peripheries.

6. As in claim 1, and having; also ventilating anddrainingperforations in the upper plate and the arch member.

7. As in claim 1 and having also a stiffener ring secured to the upper plate and arch member, intermediate their centres and peripheries and sliding bolts working in slots inthe lower edge of the stiffener ring and the lower part of the depending flange of'the anch element.

Signed at Boston, Massaclnisetts. this twenty Fourth day of July 1924-.

FREDERICK ALDEN LOVEJOY. 

